Free piston type combustion products generator for gas turbine power plants



. EXHAUST III GAS TURBINE I I m R. LEE

Filed Oct. 51, 1947 FOR GAS TURBINE POWER PLANTS coumassom May 6, 1952 COMPRESSED STARTING CHARGE CHARGE a!i H EM? E Tam w m wmfi T 0 A R% v Patented May 6, 1952 OFFICE FREE PISTON TYPE COMBUSTION vPROD- UCTS GENERATOR FOR GAS TURBINE POWER PLANTS Royal Lee, Elm Grove, Wis.

Application October 31, 1947, Serial No. 783,379

The present invention relates to combustion power apparatus, and more particularly to apparatus of the type having a combustion chamber from which combustion gases are discharged for external utilization, as in a gas turbine.

.An object of the invention isto provide a com- .bustion apparatus having improved and simplified :valve means for controlling combustion or explosion chambers.

Another object is to form two alternately acting combustionchambers in the same structure, and to provide piston valve means common to the chambers.

A further object is to provide a combustion power apparatus in which the valve-controlled combustion chambers cooperate with drivingly connected charge-compressing and gas turbine means to .form a power plant.

A still further object is to provide an improved ignition control for the combustion chambers.

The invention further consists in the several features hereinafter described and claimed.

In the accompanying drawing, illustrating certain embodiments of the invention,

Fig-1 is a diagrammatic view, partly in section.

:showing a combustion power plant arranged in :accordance with the invention, and

Fig. 2.is.a fragmentary diagrammatic sectional view .of amodified form of apparatus.

In the drawing, l designates a cylinder member closed at opposite-ends by heads I l and provided in its side walls with two sets of intake ports .l 2;and two sets of discharge or exhaust ports l3 opening into respective intake and discharge manifolds l4 and I5, each set of ports of pasrelation. The piston side walls or skirt portions are provided with two sets of intake ports 20 at opposite sides of and near the partition wall l1, and are also provided with two sets of discharge ports or passages 2| spaced from opposite sides of the partition wall H, the intake and discharge port s'2il and 2| extending transversely through the piston side walls. During reciprocation of the piston, the two sets of piston intake ports 20 are adapted to communicate alternately with the two sets of cylinder intake ports l2, and the two sets of piston dis- 1 Claim. (Cl. fill-39.76)

charge ports 2! are adapted to communicate alternately with the two sets of cylinder discharge ports l3. At eachend of piston travel,

- the piston intake ports 20 at the advanced end portion of the piston are in communication with the corresponding set of cylinder intake ports 12,

"land the piston discharge ports -2l at the other end portion of the piston are in communication with the corresponding set of cylinder discharge ports l3. The travel of the piston is relatively short, being only of suflicient extent to eifect control'of the combustion chambers. The cylin- -der member ID =forms, in effect, two tandem .cylinder'elements, and the .piston It forms, in

eifect, two tandem-connected piston elements. A compressed fuel charge is supplied to the intake manifold [4, as by'a pump or compressor 22 connected to this manifold by a conduit 23,

liquid or gaseous fuel being admitted to the conduit through a valved pipe 24. Provision may also bemade for admitting a starting charge to the combustion chambers, as by a valved pipe Z d-connected to the conduit 23.

The starting charge may consist of a compressed gas, such as butane, or a butane-air mixture. A starting charge may also be supplied by temporarily driving-the compressor from an auxiliary source of power, notshown. Ignition is here shown to .be effected by spark plugs 26 in the cylinder chines.

heads! I or other walls of the combustion chambers, and ignition timing is controlled as .hereinafter described. The combustion gases are utilized externallyof the combustion chambers,

as ina suitable motor or engine 21, preferably a gas turbine, connected by a conduit 28 to the various types, such as a turbo-compressor or a positive displacement pump, either rotary or reciprocatory.

The reciprocable piston l6 carries a lateral projection 33 which passes through an opening 34 in the cylinder side wall and alternately operates a pair of circuit-breakers 35 controlling batteryenergized primary circuits of a pair of hightension ignition coils 36, the secondary windings of which are connected to the respective spark plugs 26. Each ignition circuit per se is of more l or less conventional type. is so arranged that the travel of the piston under The ignition system the pressure of the admitted charge in each combustion chamber causes ignition to occur in that chamber. In Fig. 1, the piston is at the left-hand end of its travel, and upon its travel to the right caused by the pressure of the compressed charge the right-hand circuit-breaker will be opened, causing ignition to occur in the left-hand combustion chamber E8. The circuit-breakers can be independently adjusted to cause ignition to occur at the desired point in the travel of the valveforming piston. This adjustment may also be used to vary the frequency of operation. The adjustment of each circuit-breaker can be efiected in any suitable manner, as by shifting the circuitbreaker parallel to the direction of piston travel. The projection 33 and other similar projections, not shown, form a cooling means for the piston.

In operation, after the apparatus has been started, the compressed charge from the pump or compressor 22 is admitted alternately to the combustion chambers I8 and I9 through the cylinder ports l2 and piston ports 20. The inflowing charge serves to cool the piston partition wall I! and other nearby portions of the piston. When the piston is in the position shown in Fig. 1, the compressed charge is admitted to the left-hand combustion chamber 18, causing the piston 18 to be urged to the right and partially or completely closing the intake ports for this chamber. The right-hand circuit-breaker 35 is then opened by the piston projection 33, causing an explosion in the chamber !8 and driving the piston farther to the right, opening the discharge ports 13 for this chamber to permit the combustion gases to flow under pressure to the gas turbine 21 andalso opening the intake ports [2 for the righthand combustion chamber IS. The compressed charge then flows into the right-hand combustion chamber [9, exerting a cushioning effect on the piston. When the combustion pressure in the chamber 18 drops below the charge pressure in the chamber I9, the piston is urged to the left and in its travel the piston opens the left-hand circuit-breaker to fire the charge in the righthand combustion chamber Hi. The cycle of oper-' ation is then repeated. The gas turbine 2'! drives the compressor 22 and the net power developed is transmitted to the turbine shaft 32.

While one combustion unit is shown, it is entirely possible to provide two or more combustion units discharging into the same turbine.

The modified form of apparatus shown in Fig. 2 is generally similar to the apparatus of Fig. 1 and includesa cylinder l having mounted therein a reciprocable piston I6. Each end of the piston moves in an annular cushioning chamber 31 formed between the cylinder and inwardly projecting parts of the cylinder head II. The cylinder has inlet ports I2 and discharge ports [3, the latter being located near the outer end of the cylinder, and a spark plug 26' is placed in the side walls of the cylinder and is exposed through an opening 38 in the piston. The piston may be of a skeleton construction to reduce inertia efiects and heating. The apparatus of Fig. 2 is otherwise the same as that of Fig, l and operates in the same manner.

What I claim as new and desire to secure by Letters Patent is:

Combustion power apparatus comprising a cylinder having side walls, a fluid-pressure-operated piston reciprocable in said cylinder and forming therewith a pair of combustion chambers, and ignition means for said combustion chambers, said cylinder side walls having intake and discharge ports for each of said combustion chambers, said intake ports being adapted for connection with a source of compressed charge, said piston having an intermediate partition wall separating said combustion chambers and further having cylinder-contacting skirt portions rigidly connected with said partition wall, said skirt portions projecting from opposite sides of said partition wall and cooperating with said cylinder ports to control intake and discharge with respect to said chambers, said skirt portions having intake ports extending transversely therethrough adjacent to opposite sides of said partition wall, and

I said piston at each end of its travel exposing the intake port of the chamber at the advanced end of the piston and exposing the discharge port of the chamber at the other end of the piston.

ROYAL LEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,515,933 Crowder Nov. 18, 1924 1,629,928 Pateras Pescara May 24, 1927 1,858,102 McKeown May 10, 1932 2,011,420 Samuelson Aug. 13, 1935 FOREIGN PATENTS Number Country Date 8,881 Great Britain Apr. 2'7, 1905 280,283 Great Britain Nov. 11,192? 441,370 France May 23, 1912 

